Alert archive / Texas / Mesoscale Discussions in 2021
Mesoscale Discussion 382
The Storm Prediction Center issued this mesoscale discussion at Apr 14, 2021, 12:43 PM CDT for 14 counties in Texas. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 14, 2021, 12:43 PM CDT (17:43 UTC)
- Expired
- Apr 14, 2021, 2:45 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
Counties Bee County, TX, Colorado County, TX, DeWitt County, TX, Fort Bend County, TX, Goliad County, TX, Gonzales County, TX, Harris County, TX, Jackson County, TX, Karnes County, TX, Lavaca County, TX, Refugio County, TX, Victoria County, TX, Wharton County, TX, Wilson County, TX
The radar
The Austin/San Antonio radar (KEWX), 115 km from the middle of the area, began a volume at 17:44 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Corpus Christi, TX (KCRP), launched 12:00Z, 5.7 hours before the alert went out and 164 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 2595 J/kg
- Mixed-layer CIN
- -17 J/kg
- Mixed-layer LCL
- 477 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 16 m²/s²
- 0-3 km storm-relative helicity
- 152 m²/s²
- Significant tornado parameter
- 1.1
- Supercell composite
- 6.0
The text
As transmitted.
831
ACUS11 KWNS 141744
SWOMCD
SPC MCD 141743
TXZ000-141945-
Mesoscale Discussion 0382
NWS Storm Prediction Center Norman OK
1243 PM CDT Wed Apr 14 2021
Areas affected...portions of the Texas Coastal Plain
Concerning...Severe potential...Watch possible
Valid 141743Z - 141945Z
Probability of Watch Issuance...40 percent
SUMMARY...Storm development over the next couple of hours will be
accompanied by some increase in risk for large hail and locally
strong/damaging wind gusts through this afternoon. A WW may be
required.
DISCUSSION...Latest surface analysis shows a cold front across
western portions of the Texas Coastal Plain/eastern fringes of the
Hill Country, and then westward into the Edwards Plateau.
Meanwhile, a sea-breeze boundary has pushed into coastal counties,
with high theta-e marine air along and east of this boundary.
Though capping (near 700 mb) remains established across the area,
continued heating/mixing of the boundary layer will weaken the cap
locally -- particularly near the aforementioned surface boundaries
where ascent is locally maximized. With steep lapse rates overlying
this region above the capping layer, the destabilizing environment
-- represented by mixed-layer CAPE values now in excess of 2500 J/kg
across the region per RUC-based objective analyses -- combined with
the weakening cap will support local/robust updraft development.
While deep-layer shear is not excessive, partially owing to modest
low-level flow, ample (around 30 kt) mid-level west-southwesterlies
are contributing to shear sufficient for multicell organization, and
even some mid-level updraft rotation. As such, potential for hail
and/or locally strong outflow winds will be possible with a few of
the strongest storms. We will continue to monitor development, for
signs that convective development/coverage may warrant WW issuance.
..Goss/Thompson.. 04/14/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...HGX...CRP...EWX...
LAT...LON 29279811 29559761 29829683 29909598 30189492 29659475
28749616 28169709 28299783 28449828 28839839 29279811SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 14, 5:17 AM CDT | Mesoscale Discussion | SPC | Angelina, Hardin, Jasper, Liberty, Montgomery, Nacogdoches and 9 more | 2 hr |
| Apr 14, 1:40 PM CDT | Severe Thunderstorm Watch | SPC | Aransas, Bee, Brazoria, Calhoun, Chambers, Fort Bend and 10 more | 6 hr |
| Apr 14, 4:49 PM CDT | Mesoscale Discussion | SPC | Archer, Baylor, Callahan, Clay, Eastland, Jack and 8 more | 116 min |
| Apr 14, 5:27 PM CDT | Mesoscale Discussion | SPC | Aransas, Bee, Brazoria, Calhoun, Chambers, DeWitt and 12 more | 2 hr |
Nearby
Mesoscale Discussions in Texas, 2021Every mesoscale discussion in 2021
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.